Your Mac computer boots from the same start up disk that has been selected as the default location on your computer’s hard disk every time you turn on your Mac. When you begin to have problems starting up on your Mac system, you can change the default Mac Start-Up Disk so you can continue using your computer. There will be several places that you can select from like a different hard drive, a backup DVD, or a network startup volume.
1. Identify other Start-Up Disks
Before configuring where the Mac computer should start up from, you have to find other possible start up locations. Your Mac computer can start up on one of the available network start up volumes if your Mac is connected to a network. Select one of the computers on the network and use that computer’s start up volume as your start up disk when you restart your Mac. Another way is to start up from a Digital Versatile Disc (DVD) or an external hard drive. This process requires you to create a start up disc image on the DVD or external hard drive and then you can boot from one of those sources when you restart your Mac computer. You can also start up your computer on a particular partition on your hard drive. The process is similar to that of booting from an external source but in this procedure you will create a start up disc image on a partition on the computer hard drive.
2. Access the Startup Disk on the Mac menu
Go to the Apple menu on your taskbar at the top of your screen. Click the Apple logo to access the Menu. If you have an older Mac you can scroll down on the menu and select “Control Panel” and then on the dropdown list scroll down to the “Startup Disk” option. On a more recent Mac you select “System Preferences” on the Apple menu and then the System Preferences panel will pop up on your computer screen. Look for the “System” category on the System Preferences panel and you will find the “Startup Disk” option under it.
3. Network Startup
On the Startup Disk panel locate the globe icon which will be labeled “Network Startup” and it will serve as the available network startup volume. Depending on the Mac operating system that is made available over the network, you could be running on a later or a more recent version and it won’t affect the files on your computer. When you have selected the Network Startup volume you can restart your computer. You may be prompted to log in as an administrator to accomplish this so you should have the log in name and password.
4. System folders
At the Startup Disk panel you will see icons for the available operating system folders or operating system volumes available on your hard drive. Select another system folder or volume other than the one that has been selected as the default.
Once you have rebooted on a different startup disk you can start working on your Mac again and make the appropriate changes or repairs to get your system running again without affecting your files.